Camejo G, Olofsson S O, Lopez F, Carlsson P, Bondjers G
Instituto Venezolano de Investigaciones Cientificas, Centro de Biofisica y Bioquimica, Caracas, Venezuela.
Arteriosclerosis. 1988 Jul-Aug;8(4):368-77. doi: 10.1161/01.atv.8.4.368.
The interactions of low density lipoprotein (LDL) and apolipoprotein (apo) B-100 segments with chondroitin-6-SO4 rich aortic proteoglycans aggregate (CSPG) were studied by using quantitative frontal elution affinity chromatography. The affinity of the agarose-CSPG was higher for LDL than for very low density lipoprotein and high density lipoprotein was not bound. LDL from different individuals had dissociation coefficients (Kd) from 28 to 179 nM. Experiments with tryptic hydrolysates of apo B suggested that the capacity of LDL to bind with CSPG resides in the protein. Nine apo B-100 hydrophilic peptides, 12 to 26 amino acids long, were selected, and three were found to interact with the agarose-bound CSPG: apo B P-1 (LRKHKLIDVISMYRELLKDLSKEA, residues 4230 to 4254), apo B P-2 (RLTRKRGLKLATALSLSNK, residues 3359 to 3377), and apo B P-11 (RQVSHAKEKLTALTKK, residues 2106 to 2121). These peptides competed with LDL for binding to the agarose-bound and soluble CSPG; apo B P-2 was the most effective. This correlates with Kd values: 63, 86, and 82 microM for apo B P-2, P-1, and P-11, respectively. The peptides shared an excess of positive-charged side chains. Apo B P-2 belongs to the lys- and arg-rich, LDL-receptor domain. Apo E also binds to the agarose-proteoglycan. The results suggest that apo B regions with sequences and charge distributions analogous to those of residues 3359 to 3377, 4230 to 4254, and 2106 and 2121 are among those responsible for the interaction of LDL with intima-media CSPG.
通过使用定量前沿洗脱亲和色谱法研究了低密度脂蛋白（LDL）和载脂蛋白（apo）B - 100片段与富含硫酸软骨素 - 6 - SO4的主动脉蛋白聚糖聚集体（CSPG）的相互作用。琼脂糖 - CSPG对LDL的亲和力高于极低密度脂蛋白，且高密度脂蛋白不结合。来自不同个体的LDL的解离常数（Kd）为28至179 nM。对apo B胰蛋白酶水解产物的实验表明，LDL与CSPG结合的能力存在于蛋白质中。选择了9个长度为12至26个氨基酸的apo B - 100亲水性肽段，发现其中3个与琼脂糖结合的CSPG相互作用：apo B P - 1（LRKHKLIDVISMYRELLKDLSKEA，第4230至4254位残基），apo B P - 2（RLTRKRGLKLATALSLSNK，第3359至3377位残基）和apo B P - 11（RQVSHAKEKLTALTKK，第2106至2121位残基）。这些肽段与LDL竞争结合琼脂糖结合型和可溶性CSPG；apo B P - 2最有效。这与Kd值相关：apo B P - 2、P - 1和P - 11的Kd值分别为63、86和82 microM。这些肽段都有过量的带正电荷的侧链。apo B P - 2属于富含赖氨酸和精氨酸的LDL受体结构域。apo E也与琼脂糖 - 蛋白聚糖结合。结果表明，具有与第3359至3377、4230至4254以及2106和2121位残基相似的序列和电荷分布的apo B区域是LDL与中膜 - 内膜CSPG相互作用的原因之一。
